Viral messenger RNAs in six lines of adenovirus-transformed cells

We have compared the proteins translated in vitro using virus-specific mRNA from six lines of adenovirus-transformed cells (F4, F17, F19, REM, T2C4, and 293) with those made using RNA from productively infected cells. The mRNAs for proteins E1A-58K, 54K, 48K, and 42K, and for E1B-15K, were detected in all cell lines and for E1B-57K in at least five of the lines. Neither of the minor E1A mRNAs (for proteins 25K and 28K) found under specific conditions in infected cells were found in any transformed cell line. Two cell lines, F4 and T2C4, contained small amounts of other mRNAs encoded within region E1B including in the latter case one not detected in infected cells. The lines F4, REM, and T2C4 contain at least some E4 mRNAs, again including in the latter case one not detected in infected cells. T2C4 cells also contain E3 mRNAs, E2A-72K protein mRNA, and two E2B mRNAs, although the E2B proteins are not identical to any found in infected cells. The F19 and T2C4 lines express mRNAs encoded between 11 and 17 map units, the “IVa₂ region,” but do not include the mRNA for polypeptide IVa₂ itself. Some early mRNAs, including the “immediate early” mRNAs, have not been detected in any of these lines of transformed cells: nor did the cell lines contain any mRNAs found exclusively at late times during productive infection. Comparison of these results with the properties of the cells tentatively suggest a correlation (although not necessarily causal) between the expression of additional viral genes and increased tumorigenicity.